- 4Kb -> 4096 address locations
- 0x000 -> 0xFFF
- On the real hardware the location of 0x000 to 0x1FF was usually used to store the interpreteR.
- And the uppermost 256 bytes (0xEA0-0xFFF) were used for display refresh and the later 96 bytes were also used to store the call stack, variables and internal use.
- 16 8-bit register, V0-VF
- Usually VF is used as a flag for some instructions
- We have an address register, called "i". is 12 bits wide, used with opcodes.
- Store return addresses when subroutines are called
- Delay Timer -> Used to time things in game
- Sound Timer -> Beeping Sound
- Works drawing sprites (8 bits wide up to 15 lines high)
- Opcode are 2 bytes long stored in BigEndian format
- BigEndian: The most significant byte are in the smallest address.
| Little Endian | Big Endian |
|---|---|
| 0b1000011 | 0b1100001 |
Where N is 0 <= N < 16
| Item | Info |
|---|---|
| NNNN | Address |
| NN | 8-Bit Constant |
| N | 4-Bit Constant |
| X and Y | 4-Bit register Id |
| pc | Program Counter |
| I | 16-Bit Register (Memory Addr) |
| VN | 16 (8-Bit) Available Registers |
See here for full opcodes